Software reliability predictions for distributed software

The software reliability literature contains several models for estimating software reliability at the end of system test. However, to enable better planning, project management often needs reliability predictions prior to system test. The paper presents a software reliability prediction model that extends the known results on software predictions to the case of a distributed software architecture. The model predictions are based on software code characteristics and the size of code as distributed on the system processors. In particular, the implications of having overlapping code executing on multiple processors are examined. It is shown that the predictions, under suitable assumptions on reliability growth during system test, can be used by project management to plan their test and release time intervals. To illustrate the ideas, the prediction model is applied to a telecommunications software project. The paper explains different methods of obtaining the values of software characteristics that are needed as input to the model